BRPI0613155A2 - motor - Google Patents

Abstract

MOTOR. The present invention relates to an engine including: a crankshaft (12); a cam shaft (36); and a timing control transmission system (37) having a drive rotation member (45), a driven rotation member (46) and an endless force transmission member (47) and providing connection between the crankshaft (12) and camshaft (36). An access window (55) through which the driven rotation member (46) is fixed to and detached from the cam shaft (36) is opened on a surface of the outer end (5c) of the cylinder head (5). A lid body (57) for closing the access window (55) is attached to the outer end surface (5c). The surface of the outer end (5c) of the cylinder head (5) comprises an inclined surface (5c) which is inclined such that at least a portion of an outer periphery of the driven rotating member (46) on an opposite side of the member drive speed (45) is exposed from the access window (55). Thus, it is possible to facilitate the operation of securing the endless power transmission member to the driven rotation member and mounting the driven rotation member to the cam shaft and also contributing to engine minimization.

Description

Patent Descriptive Report for "MOTOR".

Technical Field

The present invention relates to an improvement of a motor comprising: a crank shaft supported on a crankcase; a valve operator cam shaft supported on a cylinder head; and a time-adjusting transmission system including a drive shaft fixedly mounted to the crankshaft, a drive shaft fixedly mounted to a camshaft, and an endless power transmission member wrapped around two members. rotating ends and providing a connection between the crankshaft and the camshaft; an access window through which the driven rotation member is provided in and detached from the open meat shaft on a surface of the outer end of the cylinder head and a lid body for closing the access window being attached to the surface the outer end of the cylinder head.

Prior Art

Such an engine has already been known as reported in Patent Publication 1.

Patent Publication I.Japanese Patent Application open for public inspection No. 54296-10.

Description of the Invention

Problems to Be Solved by the Invention

In conventional motors as described in Patent Publication I, a cylinder head is formed such that a surface outer end of the cylinder head in which the open access window is present outside in the axial direction of the driven rotation member and thus the driven rotation member is disposed deep within the access window. Therefore, the operation of providing the endless rotating member on the driven rotating member and mounting the driven rotating member on the camshaft is obstructed by the cylinder head around the driven rotating member, thereby deteriorating operability. Further, the integrity of the cap body bonded to the outer end surface of the cylinder head is inevitably spaced greatly apart from the rotational member driven in the axial direction, thereby impairing engine minimization.

The present invention has been embodied in view of such circumstances and is intended to provide a compact motor which exhibits good operability in providing an endless rotation member and a driven rotation member and in mounting the driven rotation member. on a meat shaft.

The present invention has a further object to easily and safely establish a predetermined phase relationship between the crankshaft and camshaft when a timing adjustment transmission system is mounted on the crankshaft and camshaft, in this case. wherein the camshaft is pre-mounted on the main motor body.

Problem Solving Means

In order to achieve the above objectives, according to a first aspect of the present invention, there is provided an engine comprising: a crank shaft supported on a crankcase; a camshaft camshaft supported on a cylinder head; and a timing adjustment transmission system including a fixedly driven rotating member mounted on the crankshaft, a fixedly driven rotating member mounted on the camshaft; and an endless power transmission member wrapped around the two rotating members and providing the connection between the crank shaft and the valve operator shaft; an access window through which the driven rotation member is provided and detached from the camshaft being opened on an outer end surface of the cylinder head and a lid body for closing the access window being joined to the outer end surface Cylinder head assembly, wherein the surface of the outer end of the cylinder head comprises an inclined surface which is inclined so that at least a portion of an outer periphery of the driven rotating member on an opposite side of the driving rotating member is exposed. from the access window.

According to a second aspect of the present invention, and according to the first aspect, the inclined surface is formed such that a half or more round portion of the driven rotation member on the opposite side of the driving rotation member is exposed from the access window.

According to a third aspect of the present invention, according to the first or second aspect, the cylinder head is overlapped via a gasket in a cylinder block that is connected to the crankcase and includes a cylinder bore and a transmission chamber. timing regulator which is present on one side of the cylinder bore and houses the timing regulation transmission system: the cylinder head is subjected to the cylinder block by a plurality of main connector bolts disposed around the cylinder bore; and the cylinder head is fixed to the cylinder block on an outer portion on one side of the time-regulating transmission chamber by an auxiliary connector screw disposed below the access window.

According to a fourth aspect of the present invention, in accordance with the first or second aspect, a sidewall of the lid body is inclined along the inclined surface of the cylinder head.

According to a fifth aspect of the present invention, according to any one of the first to fourth aspects, the engine further comprises: a first combination mark indicated on an external flush surface of the driven rotation member; a second combination mark indicated on a main motor body to match the first combination mark when the crankshaft is in a predetermined rotational position; a bolt hole provided in a hub end wall of the driven rotation member that is fitted at a portion of the end of the camshaft; a positioning groove extending radially from the bolt hole; a projecting pin provided projectively on a camshaft end surface in an eccentric position from a center of the end surface in a certain direction and engaged with the camshaft groove when the camshaft is in a predetermined relationship. Phase action relative to the crankshaft at the predetermined rotational position; a threaded hole that is provided on the end surface of the camshaft end and corresponds to the bolt hole when the camshaft is in a predetermined phase relationship to the crankshaft at the predetermined rotational position; and a mounting bolt that sieves through the bolt hole and threaded into the threaded hole to secure the cuff to the camshaft.

According to a sixth aspect of the present invention, in addition to the fifth aspect, when the camshaft is in a predetermined phase relation to the crankshaft at the predetermined rotational position, the first and second combination marks, the positioning groove and positioning pin are arranged in a line retracing through the centers of the crankshaft and camshaft.

According to a seventh aspect of the present invention, according to the sixth aspect, wherein the screw hole and the threaded hole are arranged in eccentric positions of the hub centers and the camshaft, respectively.

According to an eighth aspect of the present invention, according to the seventh aspect, wherein the threaded bore and the positioning pin are arranged in positions which are eccentric of the center of the shaft in opposite directions from each other.

The drive rotation member, the rotation member and the endless drive device respectively correspond to a drive pulley 45, a driven pulley 46 and a timing belt 47 in one embodiment of the present. invention which will be described below.

Effects of the Invention

With the first aspect of the present invention, a portion of the driven pulley exposed outside the access window can be easily held by a tool or the like without being obstructed by the cylinder head. Thus, the assembly operation of the drive shaft driven pulley is facilitated and its removal is also facilitated. Therefore, this arrangement contributes to an improvement in assembling and serviceability.

With the second aspect of the present invention, the operation of depressing and detaching the driven shaft and pulley is further facilitated, and thus the mounting and serviceability is further enhanced.

With the third aspect of the present invention, also in a portion around the time-adjusting transmission chamber, the pressures of the cylinder block surface and the cylinder head acting on the gasket are sufficiently increased by holding the cylinder head in the block. cylinder by the main connecting bolts and auxiliary In addition, the presence of the inclined surface above the auxiliary disconnect screw provides sufficient space to accept a tool for operating the auxiliary connection screw, thereby facilitating the operation of securing the connection screw and contributing to engine minimization.

With the fourth aspect of the present invention, the motor housing has a head portion whose width is narrowed towards its distal end, thereby contributing to the minimization of the motor.

With the fifth aspect of the present invention, the first and second combination marks, the screw hole, the threaded hole, the positioning groove and the positioning pin can all be arranged in a straight line passing through the centers. crankshaft and meat shaft, in sequence by performing the steps of: fixing the crankshaft in a rotational position corresponding to a specified position of the piston; inserting the driven rotation member into the endless power transmission member already wrapped around the driving rotation member while aligning the first driven rotation member combination mark with the second combination mark of the main motor body; adjusting the meat shaft positioning pin in the driven hole of the driven rotation member; and positioning pin guide for the positioning groove of the driven rotation member. Therefore, advantageously in this state where the crankshaft and camshaft have been pre-mounted on the main engine body, if the mounting bolt is threaded into the threaded bore of the thrust shaft through the driven bore of the rotating member and fixed. , the timing control transmission system can be easily and appropriately provided on the crankshaft and camshaft in their predetermined phase relationship.

With the sixth aspect of the present invention, by visually observing the state in which the first and second combination marks, positioning shaft and positioning pin are arranged in a straight line passing through the centers of the crankshaft and camshaft. It can be easily confirmed that the crankshaft and the meat shaft have established a predetermined phase relationship between the same.

With the seventh aspect of the present invention, the rotational driven rotation is safely transmitted to the carnation shaft by the single eccentric mounting bolt and the mounting bolt is prevented from being loosened.

With the eighth aspect of the present invention, it is possible to give a sufficient amount of eccentricity to each of the positioning screw bolt holes that are formed in the narrow end wall of the driven rotation member hub, thereby improving the positioning effect of the positioning groove in the positioning pin and increasing the torque capacity of the mounting bolt.

The aforementioned object, other objects, features and advantages of the present invention will be made apparent from a preferred embodiment which will be described in detail below with reference to the accompanying drawings.

Brief Description of the Drawings

Figure 1 is a plan view of a general purpose four-cycle engine according to the present invention (first embodiment).

Figure 2 is a sectional view taken along line 2 - 2 in Figure 1 (first embodiment)

Figure 3 is a sectional view taken along line 3 - 3 in Figure 1 (first embodiment)

Figure 4 is an enlarged view of an area around a crankshaft in Figure 1 (first embodiment)

Figure 5 is a view of arrow 5 in Figure 4 (first embodiment)

Figure 6 is a sectional view taken along line 6-6 in Figure 2 (first embodiment)

Figure 7 is a sectional view taken along line 7-7 in Figure 2 (first embodiment)

Figure 8 is a sectional view taken along line 8-8 in Figure 6 (first embodiment)

Figure 9 is a sectional view taken along line 9-9 in Figure 7 (first embodiment)

Figure 10 is a view from arrow 10 in Figure 8 (first embodiment)

Figure 11 is a view corresponding to Figure 10, in a state where a driven pulley is removed (first embodiment)

Figure 12 are views to describe a camshaft driven pulley mounting procedure (first embodiment).

Best Mode for Carrying Out the Invention

A preferred embodiment of the present invention is explained below with reference to the accompanying drawings.

Embodiment 1

Referring first to Figure 1 to Figure 4, a main motor body 1 of a general purpose four-cycle motor E includes: as components a crankcase 2 having at its bottom a mounting seat 2a; a cylinder block 3 integrally connected to the housing 2 having an upwardly inclined cylinder bore 3a; and a cylinder head 5 joined to an upper end face of the cylinder block 3 via a gasket 4. Four main connecting screws 6 arranged in four positions around the cylinder bore 3a and two auxiliary connecting screws 7 and 7 which will be described below, are used and for joining, that is, securing cylinder head 5 to cylinder block 3.

The crankcase 2 has an open side face; a plurality of steps 8 is integrally formed in an inner peripheral wall slightly inwardly relative to the open side face, the steps 8 are disposed towards the periphery to return to the open side face and a bearing support 10 is provided. secured to these steps via a plurality of bolts 11. This bearing bracket 10 and another housing side wall 2 support the opposite end portions of a horizontally arranged steering shaft 12 via bearings 13 and 13 '. In addition, the opposite end portions of a compensating shaft 14 disposed adjacent and parallel to the crankshaft 12 are similarly supported via bearings 15 and 15 by the bearing bracket 10 and said other housing side wall 2.

As shown in Figure 4 and Figure 5, a continuous reinforcement flange 16 is formed integrally with the outer periphery of the housing 2 so that it surrounds the plurality of steps 8 and a portion of the reinforcement flange end 16 is integrally connected to an external wall of the housing. cylinder 3, which is integral with crankcase 2.

Since the reinforcing lip 16 provides, at the outer periphery of the housing 2, a mutual connection between the plurality of steps 8, which is within the reinforcing lip 16, the stiffness with which the bearing support 10 is supported by these steps 8 and, consequently, the stiffness with which the crankshaft 12 is supported by the bearing bracket 10 can be effectively increased. As a result, the crankcase 2 may be thinned and raised. In particular, since a portion of the end of the reinforcing lip 16 is integrally connected to the outer wall of the cylinder block 3, the reinforcing function of the reinforcing lip 16 can be increased, thereby further increasing the stiffness with which the bearing support 16. 10 bearing is supported.

A side cover 17 is joined to the housing 2 via a plurality of screws 24 to close the open face on said one side of the housing 2. A portion of the end of the crankshaft 12 runs through said cover 17 and protrudes outwardly as a part. of the output shaft and an oil seal 18 is mounted on the side cover 17 to be in close contact with the outer periphery of the output shaft portion.

Referring next to Figure 1, the other end portion of the crankshaft 12 runs through said other crankcase side wall 2 and an oil seal 19 is mounted on said other crankcase sidewall 2 to be in place. intimate contact with said other end portion of the crankshaft 12 so as to be adjacent to the outside of the bearing 13 '. A flywheel 21 which also functions as a rotor of a generator 20 is attached to said other end portion of the crankshaft 12 and a cooling fan 22 is provided on the outer face of the flywheel 21. In addition, a kickback type 23 starter, which is supported on the housing 2, is arranged to face said one. another part of the end of the crankshaft 12.

In Figure 1 and Figure 3, a piston 25 fitted to cylinder bore 3a is connected to crankshaft 12 via a connecting rod 26. A combustion chamber 27 communicating with cylinder bore 3a and an inlet port 28i and a exhaust port 28e each opening - the combustion chamber 27 are formed in the cylinder head 5. An inlet valve 29i and an exhaust valve 29e are mounted on the cylinder head 5 to open and close the ends of the intake ports and 28i and 28e, respectively, which open to the combustion chamber 27. Valve springs 30i and 30e are fitted to the intake and exhaust valves 29i and 29e to propel such valves 29i and 29e in a direction in which they close. Inlet and exhaust valves 29i and 29e are opened and closed by a valve operating system 35 operating in cooperation with these valve springs 30i and 30e.

Valve operating system 35 is described with reference to Figure 3, Figure 4 and Figure 6 to Figure 12.

Referring primarily to Figure 3, Figure 4 and Figure 6, valve operating system 35 comprises a camshaft 36, a timing control transmission system 37, an intake tilt arm 38i and an exhaust tilt arm 38e. Crankshaft 36 is supported on cylinder head 5 so as to be parallel to crankshaft 12 and includes an intake cam 36i and an exhaust cam 36e. Timing transmission system 37 provides a connection between the crankshaft 23 and camshaft 36. The intake swing arm 38i provides an operative connection between intake cam 36i and intake valve 29i. The exhaust swing arm 38e provides an operative connection between the exhaust meat 36e and the exhaust valve 29β.

The camshaft 36 has opposite end portions supported by a pouch shaped bearing bore 39 and a ball bearing41, the bearing bore 39 being formed in a side wall 5a of the cylinder head 5 and the ball bearing 41 being fitted into a thrust bearing hole 40 of a dividing wall 5b in a mid section of the cylinder head 5. A common tilting shaft 42 that swings the intake and exhaust swing arms 38i and 38e has portions of the opposite end. supported by the first and second support holes 43 'and 43 formed in said side wall 5a and partition wall 5b, respectively. The first support hole 43 'of said side wall 5a is a pouch deformation and the second partition wall support 43 5b is a through hole. A set screw 44 having its top end against the outer end of the tilt axis 42 is screwed into the partition wall 5b at a portion of the outer end of the second support hole 43. The tilt axis 42 is thus prevented from moving in a thrust direction by first pocket hole 43 'and fixing screw 44.

The setscrew 44 has on its head part an integral flange seat 44a having a relatively large diameter, the flange seat 44a projecting against an outer end face of an outer rail 41a of the ball bearing 41 supporting the camshaft 36.

An inner raceway 41b of the ball bearing 41 is fitted under pressure on the camshaft 36. Thus, when the flange seat 44a of the clamping screw 44 pushes against the outer end of the outer raceway 41as described above, the camshaft 36 It is prevented from moving in a thrust direction through the pocket-shaped bearing bore 39 and flange seat 44a.

Therefore, it is possible to prevent movement in the push direction for both tilt axis 42 and camshaft 36 by means of a fastening screw 44, thereby reducing the number of valve operating system components 35, simplifying their structure. , contributing to make it compact and contributing to an improvement in the capacity of the system 35.

Timing drive system 37 comprises a toothed drive pulley 45 attached to the crankshaft 12, a toothed drive pulley 46 attached to the camshaft 36 and an endless timing belt 47 wrapped around it. of a drive pulley and driven pulley 45 and 46, the number of teeth of driven pulley 46 being twice that of drive pulley 45. The rotation of crank shaft 12 is therefore reduced by Vz by this self-regulating transmission system. 37 and transmitted to the camshaft 36. Due to the rotation of the camshaft 36, the intake and exhaust meats 36i and 36e cause the inlet and exhaust tilt arms 38i and 38e to swing against the thrust forces of valve springs 30i and 30e, respectively, opening and thereby closing the inlet and exhaust valves 29i and 29e.

This time regulating transmission system 37 is housed in a time regulating transmission chamber 48 formed by the sequential connection of a lower chamber 48a, an intermediate chamber 48b and an upper chamber 48c, the lower chamber 48a being defined between the bearing bracket 10 and the side cover 17, the intermediate chamber 48b being formed in the cylinder block 3 on one side of the cylinder bore 3a and the upper chamber 48c being formed on the cylinder head side 5. That is, the drive pulley 45 is arranged in the lower chamber 48a, the driven pulley 46 is arranged in the upper chamber 48c and the time adjusting belt 47 is arranged to run through the intermediate chamber 48b.

In this way, the space between the bearing bracket 10 and the side cover 17 is effectively used to provide the timing control transmission system 37, thereby making the engine E compact.

A valve operating chamber 49 having an open upper face is formed in the cylinder head 5 between said side wall 5a and partition 5b and the intake and exhaust shafts 36i and 36e of the drive shaft 36 and the intake and exhaust swing arms 38i and 38e, etc. are housed in the valve operating chamber 49. The open top face of the valve operating chamber 49 is closed by a head cover52 attached to the cylinder head 5 via a screw 53. The upper chamber 48c of the chamber timing transmission 48 and valve operating chamber 49 communicate between an oil passage bore 75 (see Figure 8 and Figure 11) provided on the partition wall 5b and a plurality of oil passage channels 76 (see Figures 6 and Figure 11) provided on an inner peripheral face of the bearing adjustment hole 40.

In Figure 6 to Figure 9, an access window 55 is provided on one face of the outer end 5c of the cylinder head 5, the access window 55 opening into the upper chamber 48c so that the outer side face of the driven pulley 46 is turned. access window 55. Access window 55 is used to insert driven pulley 46 into timing belt 47 and mount driven pulley 46 to camshaft 36.

A lid body 57 closing the access window 55 is joined to the outer end face 5c via a seal 56 by means of a plurality of screws 58.

As clearly shown in Figure 6, the outer end face 5c of the cylinder head 5, which the cap body is joined to, comprises a slanted face 5c that is angled so that at least apart from the outer periphery of the driven pulley 46 in the opposite the drive pulley 45 is exposed through the access window 55 and preferably at least half of the periphery of the driven pulley 46 on the opposite side the drive pulley 45 is exposed through the access window 55.

The structure with which the driven pulley 46 is mounted on the drive shaft 36 is now described.

As shown in Figure 6, driven pulley 46 comprises a bottom cylindrical hub 46a, a radially widening web 46b and a toothed hole 46c formed at the outer periphery of web 46b. Hub 46a is fitted at the outer periphery of a portion of the outer end of the projecting cam shaft 36 to the upper chamber side 48c. A hub end wall 46a is provided with a bolt hole 60 eccentrically positioned in the center of the hub 46a and a positioning sulcode 61 extending from one side of the bolt hole 60 to the eye exactly opposite the direction of the eccentricity. In addition, a first combination mark 62a is cut on one face of the outer side of the 46c and a second combination mark 62b corresponding to the first combination mark 62a is cut on the outer end face 5c of the cylinder head 5. In addition, the web 46b is provided with a plurality of through holes 64, 64 which penetrate it.

The outer end portion of the meat shaft 36 is provided, as shown in Figure 6 and Figure 11, with a threaded hole 66 corresponding to the screw hole 60 and a positioning pin 67 corresponding to the positioning groove 61.

When the crankshaft 12 is in a predetermined rotational position corresponding to a specified position (e.g., top dead center) of the piston 25 and the camshaft 36 is in a position in a predetermined phase to phase relationship. with respect to the camshaft 12, the first combination mark 62a and the second combination mark 62b, the screw bore 60 and the threaded bore 66 and the positioning groove 61 and the positioning pin 67, each coincides with one another in a straight line L which runs through the centers of the two axes 12 and 36.

When driven pulley 46 is mounted on cam shaft 36, crankshaft 12 is first fixed at the rotational position corresponding to the specified position of piston 25. Subsequently, as shown in Figure 12A, driven pulley 46 is placed inside the timing belt. 47, which has been wrapped around the drive pulley 45 previously, leading the first combination mark 62a to 46c to match the second combination mark 62b of the cylinder head 5. Next, as shown in Figure 12 (B ), when the driven pulley 46 is moved together with the timing belt 47, so that the screw hole 60 of the driven pulley 46 receives the positioning pin 67 of the camshaft 36 and the positioning pin 67 is then guided to positioning groove 61, the meat shaft 36 rotates in response thereto; and when the positioning pin 67 reaches the end of the positioning groove 61 as shown in Figure 12 (C), the bolt hole 60 and the threaded hole 66 combine at the same time that the cam shaft 36 and the hub 46a are coaxially aligned. Thus, by the remarkably simple positioning guide guiding operation 67 received by the screw hole 60 in the positioning groove 61, the first and second combination marks 62a and 62b, the screw hole 60 and the threaded hole 66 , and the positioning hole 61 and positioning angle 67 are all aligned in the straight line L which runs through the centers of the crankshaft 12 and the camshaft 36. By virtually checking this state, it can easily be confirmed that the axis hand crank 12 and camshaft 36 are in a predetermined phase relationship.

As shown in Figure 6, threading and securing mounting bolt 68 to threaded hole 66 through bolt hole 60 enables hub 46a to be secured to camshaft 36. Thus, the regulating drive system 37 is mounted on the handle shaft 12 and cam shaft 36, which are mounted on the crankcase 2 and the cylinder head 5 previously, in the predetermined phase relationship.

In this case, since screw hole 60 and threaded hole66 are positioned eccentrically in the centers of hub 46a and camshaft 36, respectively, the rotation of driven pulley 46 can be safely transmitted to cam shaft 36 via A mounting bolt 68e It is also possible to prevent the mounting bolt from loosening.

In addition, since threaded bore 66 and positioning pin 67 are eccentrically positioned, in mutually opposite directions, in the center of the camshaft 36, a sufficient degree of eccentricity can be given to each of screw bore 60 and positioning groove61, which are formed in a narrow end wall of the hub 46 of the driven pulley 46, thereby enhancing the positioning effect of positioning groove 61 relative to the positioning pin and torque capability of mounting screw 68.

As described above, since the outer end face of the cylinder head 5 in which the access window 55 opens is the inclined face 5c and the outer periphery portion of the driven pulley 46 is exposed through the access window 55, the part of driven pulley 46 exposed outside access window 55 can easily be held by a tool, etc., without interference from cylinder head 5, thereby facilitating mounting of driven pulley 46 on cam shaft 36 and its removal. Therefore, this contributes to an improvement in assemblability and ease of maintenance.

A sidewall 73 of the cap body 57 joined to the outer end face 5c of the cylinder head 5, i.e. the inclined face 5c, is formed to be inclined along the inclined face 5c. With arrangement, the head portion of the engine main body 1 is configured such that its lateral width narrows to the end side, thus making the engine E compact.

As shown in FIGS. 7 and FIG. 9, a pair of projecting portions 70 and 70 projecting externally from the access window 55 below the access window 55 is formed in the cylinder head 5; These protruding parts 70 and 70 are overlapped on one side of the upper end, on the outside of the intermediate chamber 48b of cylinder block 3 via gasket 4 and secured to cylinder block 3 via auxiliary connecting screws 7 and 7.

According to such fixing by the auxiliary connecting screws 7 and 7, it is possible to properly increase the pressure of the gasket acting surface 4 from the cylinder block 3 and the cylinder head 5 even of the intermediate chamber 48b housing the adjusting belt. In addition, since the presence of the inclined face 5c ensures sufficient clearance above the auxiliary connecting screws 7 and 7, to receive a tool for operating the auxiliary connecting screws 7 and 7, the tightening of the Auxiliary connecting screws 7 and 7 can easily be carried out. This means that the extent to which the projecting parts 70 and 70 protrude externally from the access window 55 can be made small and also contributes to making the engine E compact.

The fixing of the auxiliary connecting screws 7 and 7 is carried out before the cover body 57 is mounted.

The lubrication of the 35 valve operating system is as follows.

In Figure 1, Figure 3, Figure 6 and Figure 8, the lower chamber 48a of the time-adjusting transmission chamber 48 communicates as interior of the crankcase 2, i.e. of the crank chamber 9, through the plurality of steps 8 in the wall. of the housing 2 supporting the bearing bracket 10 and a predetermined amount of lubricating oil 71 which is common to the crank chamber 9 and the lower chamber 48a accumulates in these chambers.

As shown in Figure 3, an impeller-type oil distributor 72 is disposed in the lower chamber 48, so that part of the oil distributor 72 is submerged in the oil 71 that accumulates in the lower chamber 48a. Oil distributor 72 is driven by crankshaft 12 via gears74 and 74 '. This oil distributor 72 disperses oil 71 around by sweating and an oil guide wall 73 for guiding the dispersed oil on the timing chain side 47 is formed integrally with an outer face of the bearing bracket 10 so as to surround it. the oil distributor 72 and the periphery of the timing belt 47 on the drive pulley side 45. Since the bearing bracket 10 is a relatively small component, it can easily be fused together with the oil wall 73. Also, a Once the bearing bracket 10 has made integral with the oil guide wall 73, its stiffness is reinforced and this is also effective in increasing the stiffness with which the crankshaft 12 is supported.

In the lower chamber 48a, the oil dispersed by the oil distributor72 is guided by the oil guide wall 73 to the timing belt side 47; oil that had been deposited on timing belt 47 is transferred to upper chamber 48c by belt 47; scattering around by being jolted due to centrifugal force as the timing belt coils around the driven pulley 46; and causes it to collide with the surrounding wall to thereby form an oil mist, and the upper chamber 48c is charged with this oil mist, thereby lubricating not only the timing control transmission system 37 but also the ball bearing. 41 of the meat shaft 36.

In particular, in the upper chamber 48c, when the oil part of the timing belt 47 collides with the uninflated inner face of the lid body 57, it is also driven to the driven core 46b of the driven pulley 46. This oil passes through the through holes 64 and 64 of the driven pulley 46 and is dispersed over the ball bearing 41, thereby lubricating the ball bearing 41. Part of the oil dispersed over the ball bearing 41 moves to the operating chamber 49 through the oil passageway 76 at the outer periphery of the bearing 41 and the ball bearing 41 is therefore lubricated also from the side of the valve operating chambers 49. The lubrication of the ball bearing 41 is thus performed very well. .

As shown in Figure 3, a base portion of valve operating chamber 49 communicates with crank chamber 9 via a series of oil return passages 77 formed in cylinder head 5e of cylinder block 3 along one side. of cylinder bore 3a. Oil return passage 77 is angled downwardly to crank chamber 9 so that oil flows down from valve operating chamber 49 to crank chamber 9.

While motor E is operating, pressure pulsations occur in the crank chamber following the rise and fall of piston 25, and when pressure pulsations are transmitted to valve operating chamber 49 and timing control transmission chamber 48, through the oil return passage 77, oil passage 75 and oil passage channel 76, the oil mist moves to the middle of the valve operating chamber 49 and timing control chamber 48, In this way effectively lubricating the entire 35 valve operating system.

After lubrication, the oil that has been collected in the valve operating chamber 49 flows below the oil return passage 77 and returns to the crank chamber 9. In addition, since the face of the transmission chamber Time setting 48 is inclined downwardly to the lower chamber 48a, oil that has been collected in the upper chamber 48C flows below the intermediate chamber 48b and returns to the lower chamber 48a.

Thus, by using the operation of the oil distributor 72 and the timing control transmission system 37 and the pressure pulsations of the crank chamber 9, the interiors of the timing regulation chamber 48 and the timing operation chamber valve 49 which can be separated from each other can be lubricated with oil mist. Therefore, it is unnecessary to employ a exclusively used oil pump for lubrication, so engine structure E can be simplified and made compact and the cost can be reduced. Further, it is possible to maintain the arrangement wherein the camshaft 36 is disposed above the inlet and discharge valves 29i and 29e, thereby ensuring desired engine output performance.

The present invention is not limited to the aforementioned embodiment and may be modified in a variety of ways so long as the modifications do not depart from the spirit and scope of the invention. For example, the belt type timing transmission system 37 may be replaced with a chain type. List of Reference Numbers and Symbols

And ... engine

1 .... engine main body3 .... cylinder block3a .. cylinder hole4 .... gasket

5 .... cylinder head

5c ... outside end face = slanted face6 ... main connection screw7 .... auxiliary connection screw12 ... crankshaft35 ... valve operating system36 ... meat shaft

37 ... timing control drive system45 ... drive rotation member (drive pulley) 46 ... driven rotation member (drive pulley) 46b..cube

47 ... endless power transmission member (timing belt)

48 ... time adjusting transmission chamber48a..lower chamber48b..intermediate chamber48c..top chamber55 ... access window57 ... lid body60 ... screw hole61 ... positioning groove62a..first combination mark62b..second combination mark66 ... threaded hole67 ... positioning pin68 ... mounting screw

Claims (8)

1. Engine comprising: a crankshaft (12) supported on a crankcase (2); a valve operating cam shaft (36) supported on a cylinder head (5); and a timing adjustment transmission system (37) including a drive rotation member (45) fixedly mounted to the crankshaft (12), a driven rotation member (46) fixedly mounted to the cam shaft (36). ) and an endless force transmission member (47) wound around the rotation members (45, 46) and providing connection between the crank shaft (12) and the valve operating cam shaft (36); an access window (55) through which the driven rotation member (46) is fixed to and detached from the meat shaft (36) being opened on a surface of the outer end (5c) of the cylinder head (5) and a body of lid (57) for closing the access window (55) being joined to the outer end surface (5c) of the cylinder head (5), characterized in that the outer end surface (5c) of the cylinder head (5) ) comprises an inclined surface (5c) that is inclined such that at least a portion of an outer driven rotating member periphery (46) on an opposite side of the drive rotating member (45) is exposed from the access window (55). Motor according to Claim 1, characterized in that the inclined surface (5c) is formed so that a half-circle portion or more of the driven rotation member (46) on the opposite side of the driving rotation member (45). ) is exposed from the access window (55). Engine according to claim 1 or 2, characterized in that the cylinder head (5) is overlapped via a gasket (4) in a cylinder block (3) which is connected to the crankcase (2) and including a cylinder bore (3a) and a timing regulating transmission chamber (48) which is present on one side of the cylinder bore (3a) and housing the timing regulating transmission system (37); the cylinder head (5) is secured to the cylinder block (4) by a plurality of main connecting bolts (6) arranged around the cylinder bore (3a); and the cylinder head (5) is fixed to the cylinder block (4) on an outer portion on one side of the timing control transmission chamber (48) by an auxiliary connection screw (7) disposed below the access window (55) . Motor according to claim 1 or 2, characterized in that a sidewall of the cap body (57) is inclined along a sloping surface (5c) of the cylinder head (5). Motor according to any one of claims 1 to 4, characterized in that it further comprises: a first decombination mark (62a) indicated on a surface outside the driven rotation member (46); a second combination mark (62b) is indicated on a main motor body (I) to match the first combination mark (62a) when the crankshaft (12) is in a predetermined rotational position; a bolt hole (60) provided in a hub end wall (46a) of the driven rotation member (46) that is fitted to an end portion of the camshaft (36); a positioning groove (61) extending radially from the screw hole (60); a positioning pin (67) projectively provided on an end surface of the cam shaft (36) in an eccentric position from a center of the end surface in a right direction and engaged with the positioning groove (61) when the shaft skirt (36) is in a predetermined phase relationship on the crankshaft (12) in the predetermined rotational position; a threaded hole (66) that is provided in the end surface of the camshaft (36) and corresponds to the screw hole (60) when the camshaft (36) is in a predetermined phase relationship to the meat shaft (12) at predetermined rotational position; and a mounting screw (68) penetrating through the screw hole (60) and threaded into the threaded hole (66) to secure the hub (46a) to the camshaft (36). Engine according to claim 5, characterized in that when the camshaft (36) is in the predetermined ratio to the crankshaft (12) in the predetermined rotational position, the first and second marks of combination (62a, 62b), the positioning groove (61) and the positioning pin (67) are arranged in a straight line L that passes through the centers of the crankshaft (12) and camshaft (36). Motor according to Claim 6, characterized in that the screw hole (60) and the threaded hole 66 are arranged eccentrically from the centers of the hub (46a) and camshaft (36), respectively. . Motor according to claim 7, characterized in that the threaded bore (66) and the positioning pin (67) are arranged in positions which are eccentric of the center of the camshaft (36) in opposite directions of each other. other.